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| United States Patent |
5,616,363
|
|
Ushida
, et al.
|
April 1, 1997
|
Laminate, glass fiber non-woven fabric therefor and a method of
producing glass fiber non-woven fabric
Abstract
Glass fiber non-woven fabric for base material of laminate comprising
binder binding glass fibers to each other and having glass transition
temperature of higher than 120.degree. C.
| Inventors:
|
Ushida; Masayuki (Anzyo, JP);
Noda; Masayuki (Hikone, JP);
Ogata; Masaru (Shiga-ken, JP)
|
| Assignee:
|
Shin-Kobe Electric Machinery Co., Ltd. (Tokyo, JP)
|
| Appl. No.:
|
289243 |
| Filed:
|
August 11, 1994 |
| Current U.S. Class: |
427/372.2; 427/375; 427/379; 427/384; 427/386; 427/389.7; 427/389.8; 428/414; 428/420 |
| Intern'l Class: |
B05D 003/02; B32B 027/00; B32B 027/04 |
| Field of Search: |
428/289,414,420
427/372.2,375,379,384,386,389.7,389.8
|
References Cited
Other References
Modein Plastics Encyclopedia, Payes 140-143, 1990.
|
Primary Examiner: Ryan; Patrick
Assistant Examiner: Weisberger; R. C.
Attorney, Agent or Firm: Pearne, -Gordon, McCoy & Granger
Claims
What is claimed is:
1. A method of producing a laminate including a non-woven fabric formed of
glass fibers and impregnated with a thermosetting resin, said
thermosetting resin having a softening temperature and being heated to at
least its softening temperature during the formation of the laminate,
comprising the steps of forming a binder for said glass fibers by reacting
epoxy resin and aliphatic amine having an acid added thereto, selecting
said epoxy resin to provide said binder with a glass transition
temperature of at least 120.degree. C. and greater than the softening
temperature of said thermosetting resin, applying said binder to said
glass fibers and curing said binder to bind said glass fibers to each
other prior to impregnation with said thermosetting resin, impregnating
said fabric with said thermosetting resin, shaping said impregnated fabric
with heating of said thermosetting resin to at least its softening
temperature, and curing said thermosetting resin to form said laminate,
whereby said binder tends to resist movement of said glass fibers as the
softened resin is shaped and to restrain contraction of the cured
laminate.
2. The method of claim 1, wherein the step of forming said binder includes
using a bi-functional epoxy resin which is liquid at ordinary temperature
and an epoxy resin of poly-function of more than tetra-function, and
reacting said two kinds of epoxy resin with said aliphatic amine and
adding said acid thereto.
3. The method of claim 1, wherein the step of forming said binder also
includes using a tri-functional epoxy resin and an epoxy resin of
poly-function of more than tetra-function, and reacting said two kinds of
epoxy resin with said aliphatic amine and adding said acid thereto.
4. A method of producing a laminate including a non-woven fabric formed of
glass fibers and impregnated with a thermosetting resin, said
thermosetting resin having a softening temperature and being heated to at
least its softening temperature during the formation of the laminate,
comprising the steps of forming a binder for said glass fibers by reacting
epoxy resin and aliphatic amine having an acid added thereto, selecting a
tri-functional epoxy resin as said epoxy resin to provide said binder with
a glass transition temperature of at least 120.degree. C. and greater than
the softening temperature of said thermosetting resin, applying said
binder to said glass fibers and curing said binder to bind said glass
fibers to each other prior to impregnation with said thermosetting resin,
impregnating said fabric with said thermosetting resin, shaping said
impregnated fabric with heating of said thermosetting resin to at least
its softening temperature, and curing said thermosetting resin to form
said laminate, whereby said binder tends to resist movement of said glass
fibers as the softened resin is shaped and to restrain contraction of the
cured laminate.
5. A method of producing a laminate including a non-woven fabric formed of
glass fibers and impregnated with a thermosetting resin, said
thermosetting resin having a softening temperature and being heated to at
least its softening temperature during formation of the laminate,
comprising the steps of providing a binder for said fabric glass fibers by
reacting epoxy resin and aliphatic amine having an acid added thereto,
said epoxy resin being selected to provide said binder with a glass
transition temperature of at least 120.degree. C. and greater than the
softening temperature of said thermosetting resin, applying said binder to
said glass fibers and curing said binder to bind the glass fibers to each
other prior to impregnation with said thermosetting resin, impregnating
said fabric with said thermosetting resin, shaping said impregnated fabric
with heating of said thermosetting resin to at least its softening
temperature, and curing said thermosetting resin to form said laminate.
Description
BACKGROUND OF THE INVENTION
This invention pertains to laminate, glass fiber non-woven fabric for base
material of laminate and a method of producing the glass fiber non-woven
fabric.
Glass non-woven fabric has been conventionally used for base material of
electrically insulating laminate. The laminate has been produced by
impregnating the base material with thermosetting resin and forming them
under heat and under pressure. The glass non-woven fabric before
impregnated with thermosetting resin has glass fibers bound by binder to
each other.
The binder has been conventionally produced as disclosed in Japanese patent
Application Publication No. 39474/1977, for example. In this Publication,
1,2 epoxide compound having more than two oxilane functions included in a
molecule and having epoxy equivalent of 170 through 1000 is reacted with
water-soluble polyamine compound having more than at least one active
hydrogen bound with nitrogen atom at a ratio of more than 1/4 of the
active hydrogen in the water-soluble polyamine compound relative to one
oxylane function in the epoxide compound. The thus obtained product has an
acid added thereto to induce water-soluble or water-dispersed
amine-epoxide acid salt which is quickly cured under heat.
The disclosed binder has glass transition temperature of about 95.degree.
C. and is produced by using 40 weight parts of solvent in order to improve
a control of reaction progress.
However, thermosetting resin laminate having base material of glass fiber
non-woven fabric produced by binding glass fibers to each other by the
conventional binder tends to have contraction in size produced while the
laminate is processed under heat.
In addition thereto, a large quantity of solvent has to be used for
producing the conventional binder.
SUMMARY OFT HE INVENTION
A principal object of the invention is to provide a thermosetting resin
laminate having glass fiber non-woven fabric adapted to be prevented from
having contraction in size produced therein.
Another object of the invention is to provide glass fiber non-woven fabric
adapted to be prevented from having contraction in size produced therein.
Further object of the invention is to provide a method of producing glass
fiber non-woven fabric adapted to be prevented from having contraction in
size produced therein.
Further object of the invention is to provide a method of producing glass
fiber non-woven fabric adapted to obtain binder therefor while a smaller
amount of solvent is used.
In accordance with one aspect of the invention, there is provided a
laminate comprising base material impregnated with thermosetting resin and
formed under heat and under pressure, at least one portion of said base
material comprising glass fiber non-woven fabric having glass fibers bound
to each other by binder having glass transition temperature of higher than
120.degree. C.
In accordance with another aspect of the invention, there is provided glass
fiber non-woven fabric for a laminate having glass fibers bound to each
other by binder having glass transition temperature of higher than
120.degree. C.
In accordance with further aspect of the invention, there is provided a
method of producing glass fiber non-woven fabric having glass fibers bound
to each other by binder comprising a reactant of epoxy resin and aliphatic
amine having an acid added thereto, said method characterized by using as
said epoxy resin bifunctional epoxy resin which is liquid at ordinary
temperature and epoxy resin of poly-function of more than tetra-function,
said two kinds of epoxy resin being reacted with said aliphatic amine and
having said acid added thereto.
In accordance with further aspect of the invention, there is provided a
method of producing glass fiber non-woven fabric having glass fibers bound
to each other by binder comprising a reactant of epoxy resin and aliphatic
amine having an acid added thereto, said method characterized by using as
said epoxy resin tri-functional epoxy resin and epoxy resin of
poly-function of more than tetra-function, said two kinds of epoxy resin
being reacted with said aliphatic amine and having said acid added
thereto.
In accordance with further aspect of the invention, there is provided a
method of producing glass fiber non-woven fabric having glass fibers bound
to each other by binder comprising a reactant of epoxy resin and aliphatic
amine having an acid added thereto, said method characterized by using
tri-functional epoxy resin as said epoxy resin, said epoxy resin being
reacted with said aliphatic amine and having said acid added thereto.
Since the binder for the glass fiber non-woven fabric of the invention
binding glass fibers to each other have the glass transition temperature
higher than the conventional binders, they are never softened when the
laminate produced by using the glass fiber non-woven fabric of the
invention is formed under heat and under pressure even though the
thermosetting resin with which the glass fiber non-woven fabric is
impregnated is molten and softened. Thus, the binder never moves together
with the molten resin so that it is never extended and broken with the
result that the laminate is restrained from having contraction in size
produced therein.
It should be noted that the glass transition temperature of the binder for
the glass fiber non-woven fabric is essentially higher than 120.degree. C.
(including 120.degree. C.) for restraining the laminate from being
contracted in size because curing reaction of the molten thermosetting
resin is rapidly progressed as the forming temperature of the laminate is
raised until it reaches 120.degree. C. and has a higher viscosity so that
it is no longer fluid.
In this manner, since glass fibers are kept to be bound to each other until
the thermosetting resin is cured and no longer fluid, the binder can
accomplish its function.
As the glass transition temperature of the binder exceeds 120.degree. C.,
the laminate can be prevented from being more positively contracted in
size. Although the thermosetting resin is cured and less fluid, it will
expand and slightly move due to its formation pressure. As the glass
transition temperature of the binder becomes higher and higher, the glass
fibers of the glass fiber non-woven fabric can be positively bound to each
other by the binder against the movement of the thermosetting resin due to
its expansion.
Since the bi-functional epoxy resin which has lower relative reaction
functions as reactive dilution agent for poly-functional epoxy resin which
is epoxy resin of more than tri-function and which has higher relative
reaction, the progress of the reaction can be controlled even though the
quantity of solvent for reaction system is reduced.
Since the reaction of the tri-functional epoxy resin with the aliphatic
amine is nearly that of the bi-functional epoxy resin, the quantity of
solvent can be reduced when a single system of only the tri-functional
epoxy resin is used.
When both of the tri-functional epoxy resin and epoxy resin of more than
tetra-function are used, the quantity of solvent can be also reduced
because the former serves as reactive dilution agent for the latter.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and features of the invention will be apparent
from the description of the embodiments of the invention taken along with
reference to the accompanying drawings in which;
FIG. 1 illustrates variations in size contraction ratio while laminates are
processed in various manners;
and FIG. 2 illustrates relationship of glass transition temperature of
binder for glass fiber non-woven fabric with size contraction of the
laminates having the glass fiber non-woven fabrics used therein.
DETAILED DESCRIPTION OF THE EMBODIMENTS
As aforementioned, laminates of the invention comprise base material
impregnated with thermosetting resin and formed under heat and under
pressure. At least one portion of the base material comprises glass fiber
non-woven fabric having glass fibers bound to each other by binder having
glass transition temperature of higher than 120.degree. C. (including
120.degree. C.).
The binder comprises a reactant of epoxy resin and aliphatic amine having
an acid added thereto. Epoxy resin used for the invention may be
combination of bi-functional epoxy resin which is liquid at ordinary
temperature and epoxy resin of poly-function of more than tetra-function.
The two kinds of epoxy resin are reacted with aliphatic amine and have
acid added thereto.
Otherwise, epoxy resin may be combination of tri-functional epoxy resin and
epoxy resin of poly-function of more than tetra-function. The two kinds of
epoxy resin are reacted with aliphatic amine and have acid added thereto.
Alternatively epoxy resin may be tri-functional epoxy resin, which is
reacted with aliphatic amine and has acid added thereto.
Bi-functional epoxy resin which is to be used for the invention and which
is fluid at ordinary temperature may be bis-phenol A type epoxy resin
while poly-functional epoxy resin including tri-functional epoxy resin may
be phenol-novolac-epoxy resin, cresol-novolac epoxy resin, his-phenol A
type novolac epoxy resin and the like.
Amine for curing agent may be water-soluble polyamine of straight chain
aliphatic amine such as diethylene-triamine and triethylene-tetramine, but
it is not limited thereto.
Solvent for controlling the reaction may be of any type except for alcohol
such as methanol which is reactive with epoxy resin.
Acid for neutralizing aliphatic amine may be organic acid such as formic
acid and acetic acid having no harm to human body during drying step while
the glass fiber non-woven fabric is produced, but it will be understood
that it is not limited thereto.
(LAMINATE AND GLASS FIBER NON-WOVEN FABRIC)
As shown in Table I, there were prepared various glass fiber non-woven
fabrics I through XII having binders of various glass transition
temperatures Tg used therefor. In this table, "GBNF" means glass fiber
non-woven fabric while "Tg" means glass transition temperature
(.degree.C.), which was measured by thermal mechanical analyzer (TMA
method). The above binders used in the glass fiber non-woven fabrics I
through XII were produced by Examples, Comparisons and Prior Art I through
XII described later with respect to production of glass fiber non-woven
fabrics.
TABLE I
______________________________________
GBNF I II III IV V
______________________________________
Tg 125 135 122 135 140
______________________________________
GBNF VI VII VIII IX X
______________________________________
Tg 145 152 205 143 96
______________________________________
GBNF XI XII
______________________________________
TG 165 200
______________________________________
Prepregs were produced by impregnating these glass fiber non-woven fabrics
with epoxy resin and drying them. Thereafter, copper foils were placed on
both sides of the two prepregs superposed one upon another and formed
under heat and under pressure to produce laminates.
It was found that the thus produced laminates have had such
size-contraction rate during their working process as varied as shown in
FIG. 1.
It was also found that the laminates have had variation in size-contraction
rate of FIG. 1 after their final thermal working process relative to the
glass transition temperature Tg as shown in FIG. 2.
It will be noted from FIG. 1 that as the glass transition temperature Tg of
the binders raises, the size-contraction rate of the laminates is reduced.
It will be also noted from FIG. 2 that the size-contraction rate of the
laminates is more remarkably and more effectively reduced at the glass
transition temperature of higher than 120.degree. C.
Glass fiber non-woven fabrics were produced by paper-making glass fibers
and spraying binders thereto, which will be described in detail. In
Examples of the invention, Comparison and Prior Art, epoxy resin selected
from ones shown in TABLE II was used, penta-ethylene-hexamine was used as
aliphatic amine, acetone as organic solvent and acetic acid as reaction
termination agent. In these Examples, Comparisons and Prior Art, all of
active hydrogen equivalent ratio of amine/epoxy resin was 1. In table II,
Maker "A" is YUKA SHELL Co. LTD., Japan, "B" TOHTO KASEI Co. LTD., Japan
and "C" MITSUI OIL CHEMICAL Co. Ltd., Japan.
TABLE II
______________________________________
Tradename Type of epoxy resin
maker
______________________________________
EPIKOTE 828 bis-phenol A type
A
bi-functional
EPIKOTE 157S70 bis-phenol A novolac
A
type poly-functional
EPIKOTE 1032 glycygylized tris-
A
phenylole methane type
tri-functional
YDPN-638 phenol novolac B
poly-functional
YDCN-704 cresol novolac B
poly-functional
VG 3101 glycygylized tris-
C
phenylole methane type
tri-functional
______________________________________
EXAMPLE I
To 50 weight parts of EPIOKTE 828, 50 weight parts of YDPN-638 (Table II)
and 13.2 weight parts of triethylene tetramine was added and combined 37.7
weight parts of acetone. Then, they were reacted with each other at
ordinary temperature for eight hours while fully agitated and thereafter
have 1019 weight parts of 10% acetic acid aqueous solution added thereto
to produce binder for glass fiber non-woven fabric.
EXAMPLE II
To 100 weight parts of YDPN-638 (Table II) and 13.6 weight parts of
triethylene tetramine was added and combined 61.2 weight parts of acetone.
Then, they were reacted with each other at ordinary temperature for eight
hours while fully agitated and thereafter have 1022 weight parts of 10%
acetic acid aqueous solution added thereto to produce binder for glass
fiber non-woven fabric.
EXAMPLE III
To 70 weight parts of EPIOKTE 828 (Table II), 30 weight parts of YDCN-704
(Table II) and 12.4 weight parts of triethylene tetramine was added 28
weight parts of acetone. Then, they were reacted with each other at
ordinary temperature for eight hours while fully agitated and combined and
thereafter have 1012 weight parts of 10% acetic acid aqueous solution
added thereto to produce binder for glass fiber non-woven fabric.
EXAMPLE IV
To 50 weight parts of EPIOKTE 828 9 (Table II), 50 weight parts of YDCN-704
and 12.1 weight parts of triethylene tetramine was added 45 weight parts
of acetone. Then, they were reacted with each other at ordinary
temperature for eight hours while fully agitated and combined thereafter
have 1009 weight parts of 10% acetic acid aqueous solution added thereto
to produce binder for glass fiber non-woven fabric. (EXAMPLE V)
To 30 weight parts of EPIOKTE 828 (Table II), 70 weight parts of YDGN-704
(Table II) and 11.8 weight parts of triethylene tetramine was added 60.2
weight parts of acetone. Then, they were reacted with each other at
ordinary temperature for eight hours while fully agitated and combined and
thereafter have 1006 weight parts of 10% acetic acid aqueous solution
added thereto to produce binder for glass fiber non-woven fabric.
EXAMPLE VI
To 100 weight parts of YDCN-704 (Table II) and 11.3 weight parts of
triethylene tetramine was added 74.2 weight parts of acetone. Then, they
were reacted with each other at ordinary temperature for eight hours while
fully agitated and combined and thereafter have 1002 weight parts of 10%
acetic acid aqueous solution added thereto to produce binder for glass
fiber non-woven fabric.
EXAMPLE VII
To 50 weight parts of EPIOKTE 828, (Table II) 50 weight parts of VG 3101
and 12.2 weight parts of triethylene tetramine was added 28 weight parts
of acetone. Then, they were reacted with each other at ordinary
temperature for eight hours while fully agitated and combined and
thereafter have 1010 weight parts of 10% acetic acid aqueous solution
added thereto to produce binder for glass fiber non-woven fabric.
EXAMPLE VIII
To 100 weight parts of VG 3101 (Table II) and 11.6 weight parts of
triethylene tetramine was added 48 weight parts of acetone. Then, they
were reacted with each other at ordinary temperature for eight hours while
fully agitated and combined and thereafter have 1004 weight parts of 10%
acetic acid aqueous solution added thereto to produce binder for glass
fiber non-woven fabric.
EXAMPLE IX
To 100 weight parts of EPIKOTE 157S70 (Table II) and 11.8 weight parts of
triethylene tetramine was added 74.5 weight parts of acetone. Then, they
were reacted with each other at ordinary temperature for eight hours while
fully agitated and combined and thereafter have 1006 weight parts of 10%
acetic acid aqueous solution added thereto top produce binder for glass
fiber non-woven fabric.
PRIOR ART X
To 100 weight parts of EPIKOTE 828 (Table II) and 15.3 weight parts of
pentaethylene hexamine was added 99.4 weight parts of acetone. Then, they
were reacted with each other at a temperature of 60.degree. C. for three
hours while fully agitated and combined and thereafter have 1038 weight
parts of 10% acetic acid aqueous solution added thereto to produce binder
for glass fiber non-woven fabric.
EXAMPLE XI
To 70 weight parts of EPIKOTE 157S70 (Table II), 30 weight parts of EPIKOTE
1032 (Table II) and 12.8 weight parts of triethylene tetramine was added
48.4 weight parts of acetone. Then, they were reacted with each other at
ordinary temperature for three hours while fully agitated and combined and
thereafter have 1015 weight parts of 10% acetic acid aqueous solution
added thereto to produce binder for glass fiber non-woven fabric.
EXAMPLE XII
To 100 weight parts of EPIKOTE 1032 (Table II) and 14.9 weight parts of
triethylene tetramine was added 49.2 weight parts of acetone. Then, they
were reacted with each other at ordinary temperature for three hours while
fully agitated and combined and thereafter have 1034 weight parts of 10%
acetic acid aqueous solution added thereto to produce binder for glass
fiber non-woven fabric.
In these Examples, Comparisons and Prior Art, the rate of solvent relative
to reactant solution was shown in TABLE III. This Table has glass
transition temperature of the thus obtained binders also indicated
thereon. Examples I, III through V, VII and VIII, Comparisons II, VI and
IX, and Prior Art X correspond to those in Table I.
TABLE III
______________________________________
I II III IV V
______________________________________
Solvent (weight parts)
25 35 20 30 35
TG .degree.C.
125 135 122 135 140
______________________________________
VI VII VIII IX X
______________________________________
Solvent (weight parts)
40 20 30 40 46
TG .degree.C.
145 152 205 143 96
______________________________________
XI XII
______________________________________
Solvent (weight parts)
30 30
Tg .degree.C. 165 200
______________________________________
It will be noted from Table III that according to Examples I, III through
V, VII and VIII of the invention, there were produced binders having glass
transition temperature of more than 120.degree. C. while the reaction was
controlled having a smaller amount of solvent used therefor, which
advantageously causes the amount of solvent to be saved.
Although some examples of the invention have been illustrated and described
with reference to the accompanying drawings, it will be understood that
they are by way of examples and that various changes and modifications may
be made without departing from the spirit and scope of the invention,
which is defined only by the appended claims.
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